In general, the ability of a surfactant to lower the surface tension of a solvent or formulation has little predictive value to determine where that surfactant would be useful as leveling agents to prevent coating defects. To prevent coating defects a surfactant only has to lower the surface energy of a formulation on drying only marginally, but in order to prevent coating defects such as orange peel or cratering (i.e., formation of surface blemishes in a freshly coated surface, usually in the form of small round patches), it should be capable of maintaining that surface energy at a nearly constant value during drying. However, drying behavior of a two component system of resin and solvent may lead to surface gradients in surfactant that is present as reported, for example, by D. E. Weidner in “Role of Surface Tension Gradients in Correcting Coating Defects in Corners” in Journal Of Colloid And Interface Science, vol. 179, pp 66-75 (1996). For example, FIG. 10of that paper reports that under some circumstances weaker surfactants may result in coatings with greater thickness at the edges, and hence more level, than if stronger surfactants are used.
Hence, in Edisonian fashion, one is ultimately left with the option of empirically evaluating different surfactants in order to determine which might be effective in certain types of formulations.